This invention relates to oral compositions containing an anticalculus agent which is a combination of a phosphorus-containing compound and a polymer selected from homopolymers of a carboxylic monomer and copolymers thereof containing at least 30% of said carboxylic monomer. This invention also relates to a method for inhibiting dental calculus on teeth.
Tartar or dental calculus is calcified plaque and plaque is the culprit of gum disease. Tartar is a deposit which forms on the surfaces of the teeth at the gingival margin. Mature calculus consists of an inorganic portion which is largely calcium phosphate arranged in a hydroxyapatite crystal lattice structure similar to bone, enamel and dentine. An organic portion is also present and consists of salivary sediment, food debris, and various types of microorganisms.
It is generally agreed that calcium and orthophosphate form the crystalline material known as hydroxyapatite which is dental calculus, i.e., a mineralized, hard formation which forms on teeth. The precursor to crystalline hydroxyapatite is amorphous calcium phosphate which differs from hydroxyapatite in atomic structure, crystal morphology, and stoichiometry. The x-ray diffraction pattern of amorphous calcium phosphate shows broad peaks typical of amorphous materials which lack the long range atomic order characteristic of all crystalline materials, including hydroxyapatite.
It is generally well known that linear molecularly dehydrated polyphosphates, such as hexametaphosphate, tripolyphosphate, pyrophosphate, and the like, are effective calcium and magnesium ion suppressors, inhibitors, sequestrants and/or chelating agents. Such materials are also known to be effective inhibitors of hydroxyapatite formation in vitro. It is also known that such polyphosphates, when introduced into the oral cavity and/or saliva, are significantly hydrolyzed by salivary enzymes, i.e., polyphosphates to orthophosphates which are ineffective as inhibitors of hydroxyapatite formation.
Studies have shown that there is a good correlation between the ability of a compound to prevent hydroxyapatite crystalline growth in vitro and its ability to prevent calcification in vivo, provided that such compound is stable in and inert to saliva and its components.